The battle over George Orwell's political legacy is set to reignite next month when his notebook naming suspected communist sympathisers goes on public display for the first time.

The document proves that Orwell, long lionised by the Left, was not averse to scrutinising 135 possible 'cryptos' or 'fellow travellers', including the novelist and playwright J.B. Priestley, the Scottish poet Hugh McDiarmid, the novelist Naomi Mitchison and the Labour MP Ian Mikardo.

The book formed the basis of a list Orwell sent to his close friend Celia Kirwan in May 1949. Kirwan had just started work in the semi-secret Foreign Office Information Research Department, investigating potential anti-communist propagandists. Orwell, the author of Animal Farm and Nineteen Eighty-Four, offered to compile a list of those 'who should not be trusted as propagandists [for the West]' in the escalating cold war.

The final list contained 38 names of journalists, scholars and actors, including film comic Charlie Chaplin, actor Michael Redgrave, historian E.H. Carr and left-wing Labour MP Tom Driberg. Its discovery earlier this year was proof that Orwell, after conscientious second thoughts and deletions, had sent the Foreign Office some names from his notebook drafts.

The key notebook, kept until now in the Orwell Archive at University College, London, contains entries in ballpoint, pen and pencil, with asterisks in red and blue against some names. Of the 135 names, 10 have been crossed out, either because the person had died - like F. La Guardia, the mayor of New York - or because Orwell had decided they were not crypto-communists. The name of the historian A.J.P. Taylor is crossed out, with Orwell's heavily underlined remark 'Took anti-CP line at Wroclaw Conference'.

Mitchison is dismissed as a 'sentimental sympathiser only', while Joseph McCabe, whose job is named as books and pamphlets, is 'v. stupid'. McDiarmid is noted for his 'Scottish nationalism. Very anti-English'. Against Mikardo's name is the question: '(Jewish?)'. Orwell's agonising over his individual judgements is shown by the entry on Priestley, which has against it a red asterisk, crossed out with black cross-hatching and then encircled in blue with an added question-mark.

Orwell began keeping the notebook in the Forties. Kirwan had turned down his marriage proposal, which has caused speculation that he was motivated by love. Others have sought to use the notebook to portray Orwell as a 'socialist icon who became an informer'.

But D.J. Taylor, author of a recent Orwell biography, said last night: 'He was deeply paranoid about communists, but there was good reason to be paranoid at that time because there were people like Guy Burgess walking around the corridors of power. People have been looking for ammunition they can throw back at Orwell, but I don't think this does any harm to his reputation.'

The notebook goes on display at a free exhibition, 'Orwell Observed', opening on 5 November at The Newsroom, the Guardian and Observer archive and visitor centre at 60 Farringdon Road in London. The exhibition has many artefacts, including submissions from his time at The Observer.

There will also be seminars hosted by Observer writers, and screenings of the Bafta award-nominated Animal Farm.